Research On Land Subsidence Monitoring Based On Time Series InSAR

Land subsidence is a kind of geological disaster that the ground slowly descends,and it has features of slow,permanent.In the early stage of social development,land subsidence did not cause much concern.With the development of society,land subsidence has been continuously intensified,and it has become a relatively serious geological disaster affecting the sustainable development of many countries.It poses a threat to people's lives,and the losses of environmental and economic caused by it each year are difficult to estimate.Obtaining accurate land subsidence information and analyzing its evolution rules are important basis for ground subsidence prevention and control.Conventional ground settlement monitoring means,for example,GPS measurements,have their own advantages,but they can not get large area datas.InSAR measurement technology has a characteristic that it can monitor a wide range,and it is suitable for surface settlement monitoring and other disaster prediction.D-InSAR technology is limited by factors such as time decoherence and spatial decoherence,which usually reduces the accuracy of the monitoring results.SBAS technology used in surface deformation monitoring has its own unique advantages,which can overcome the decoherence in time and space,and unlike other time Series InSAR,SBAS-InSAR technology does not require a large number of images in the study area.This article describes the differential interferometry technology,describes the basic principle of InSAR interferometry and D-InSAR measurement,then analyzes the main sources of error and the limiting factors of D-InSAR measurement,then introduces the principle,the principle and flow of PS-InSAR and SBAS-InSAR technology,and analyzes the main technologies of SBAS-InSAR technology in data processing.In this study,collected 25 Sentinel-1A data in Dali Haidong New City from May 2016 to October 2017,and used PS-In SAR and SBAS-In SAR in study area.By generating connection diagrams,interference workflow,PS inversion,geocoding and other processing,the settlement of the study area is obtained.In order to evaluate the accuracy of the SBAS technique for the processing results of the data obtained,this article compares and verifies the observed values of the ascending and descending track.The fitted linear equation is y=1.018x-0.3046,the error is ± 1.86mm/a,the analysis shows that the two sets experimental results of the ascending and descending track have high consistency and correlation.In order to show the InSAR surface subsidence monitoring results better,this article uses a three-dimensional expression.Fusion calculation of the same name points of the ascending and descending track,then use the linear interpolation algorithm for interpolation,draw a 3D sedimentation rate map of data fusion sinking funnel.The analysis shows that site leveling may be the main cause of land subsidence in Dali Haidong New City.Experimental results prove that using Sentinel-1A data and SBAS-InSAR technology,it is possible to obtain ground subsidence changes in Dali Haidong New City,and provide support for the prevention and control of land subsidence.